> To speed up your SSR, render components, not the _whole_ page.
That is totally wrong. Rendering components again and again is not performant at all. "Rendering components, storing them somewhere and finally when user requests, stitch them and give it to the user." Is that your solution ? That would be even more expensive than normal rendering.
> your users are _still_ going to see the 810ms latency the first time they access your service
That is not true too. Only one user will see the 810ms latency. All the users, when access this page, will get sub 20ms response time. Have you ever worked with servers/caching and know how they work ?